Producing colored photographic prints in graduated relief.



UNITED STATES PATENT ormon.

FREDEEIG E. IVES, 0F WEEHAWKEN, NEW JERSEY.

, PRODUCING COLORED PHOTOGBAPHIC PRINTS IN GRADUATED BELIEF.

980,962. 110 Drawing.

Specification of Letters Patent. Patented J an." 10, 1911. Applicationfiled April 28, 1910. Serial N0. 558,230.

To all,w7wm it may concern:

Be it known that I, FREDERIG E. has, acitizen of the United States,residing in lVoodclifi'e on Hudson, Weehawken, New Jersey, have inventedcertain Improvements in Producing Colored Photographic Prints inGraduated Relief, of which the following is a specification. v

My invention is an improvement upon a method which I described in apaper published in the Journal of the Camera Club, London, April, 1894,page 63, as follows: The examples which I shall show were made fromphotochromoscope negatives. Bichromatized gelatin films on clearcelluloid were exposed from the back by electric light, developed ascarbon prints, the images cut apart and each dyed to a suitable depth byimmersion in a solution of its proper printing color. great degree ofprecision is necessary to secure the correct proportionate depth ofcoloring in the three prints.

The above described process was not as practical as was desired for thefollowing among other reasons: 1. Celluloid films thick enough to besatisfactorily coated-with the necessary thickness of gelatin for theprocess were objectionable because of color and of shrinkage andtendency to buckle throughgradual'evaporation or solution of containedcamphor, and because when the prints were used as lantern slides theeffectof heat in the lantern upon the celluloid was liable to destroy orseriously damage the pictures. 2. The bichromated gelatin film must beofsuch thickness that detail may be retained in the prints from both endsof the scale of gradation from blackto white of the negative, and owingto the small percentage of 'bichromate salt that can be incorporatedwith elatin without crystallization in drying, t egelatin film must beso thick as to make the process of development in warm water tediouslyslow, and the resulting print' diflicult to color up correctly, since ifthe color bath roved to have been too strong for the su ject, washing toreduce the strength acted relatively too fast upon the thin: parts, andstrengthening by the use of.

a stronger dye bath, also acted relatively too fast on the thin arts. 3.The finished color prints were sel om as sharp as is desirable, and therelief was so great that it became necessary, in order to obtainsatisfactory results withthe lantern slides, to

seal the prints together with Canada balsam.

By my improved process these difliculties and defects are greatlyreduced, and the -stituting amyl acetate collodlon for celluloid,second, by using a more soluble sensitizer which permits of theincorporation of a much larger percentage of the sensitizing salt in thegelatin without danger of crystallization in dryin thus obtaining printsin lower relief, an third, by treating the .developed low relief printswith chromic acid in order both to sharpenthem and to serve as a mordantfor the dyes subsequently used, and which would not be sufiicientlymordanted by the small amount of chromic oxid remaining in the lowrelief prints after development 1n an" alkaline developer. I sometimesincorporate a nonactinic d 6 with the sensitizing solution, to limit t epenetration of light, this dye being preferably acid, so that it may bedischarged by an alkaline developer.

Either gelatin or fish glue may be usedas the coating on the amylacetate collodion film, said coating being sensitized with bichromate ofammonium. If a gelatin coating is used the sensitizing may be done byimmersing the gelatin coated film for a minute or two in a solution ofbichromate of ammonium, either with or Without the addition of anon-actinic dye, then drying superficiall by placing between blotters orby means 0 a squeegee, before hanging up to dry out in the usual way.The removal of the superfluous sensitizer, asdescribed, is in order toprevent uneven sensitizing and probable crystallization of bichromatesalt 1n or on the surface of the gelatin coating. If fish glue is used,the sensitizer or sensitizer and dye must be incorporated in the fishglue solution before coating, as fish glue is soluble in the coldsensitizing bath.

The gelatin prints are-developed in warm or hot water, to which I preferin any case to add a small amount of ammonia, although it may not alwaysbe necessary, since even when the dye is used, it may be discharged byammonia after the develo ment is completed. Bromid or iodid of silvermay also be incorporated in the gelatin or fish glue coating, in whichcase it should be dissolved out by hyposulfite of soda after the reliefprint is developed.

and cleared as above described, it is not, even if dried out, as sharplydefined as 1s usually desirable, and the print will not readily absorbor fix enough dye for the purposes of the process. The next and one ofthe most important procedures in my improved method is therefore toimmerse the print for a minute or two in a solution of chromic acid,which may be of the strength of 30 grains of chromic acid to one pint ofWater. This treatment contracts, sharpens up and hardens the reliefprint, and mordants it for the dyes subsequently used, so that verysharply defined and exceedingly low relief prints may bemade and dyed tothe desired depth of color. The prm [S may be transferred directly fromthe chromic acid bath to the respective dye baths, or first washed inwater. Three such prints are made for the composite trichromatic print.Oneprint from a negative made with red light is dyeda peacock blue, onefrom a negative made with green light is dyed a magenta color, and oneprint from a negative made with blue light is dyed yellow. The threeprints superposed make the complete composite trichromatic print. Thedyes which I prefer to use, and which are mordanted by chromic oxid, areneptune green, a mixture of acid rhodamine and eosin, and brilliantyellow.

Another advantage of the chromic acid treatment is that it facilitatesthe drying of the prints by first pressing them between blotters toabsorb the surplus water. Ordinarily such use of blotters is notpermissible as the fluff from the same sticks to the prints and cannotafterward be brushed off. When the-chromic acid treatment is adoptedthis objection is overcome.

I claim:

1. The within described improvement in the'process of making coloredphotographic prints in graduated relief, the same ponsisting in firstproducing and developing a colloid relief print, then treating saidprint with a hardening and'mordanting agent such as chromic acid, andthen dyeing the print thus treated.

2. The within described improvement in the process of making coloredphotographic prints in graduated relief, the same consisting inincorporating a non-actinic coloring medium in the sensitized colloidcoating, exposing said sensitized coatin to light, developing the print,discharglng the coloring medium, treating the developed relief printwith a hardening and mordanting agent such as chromic acid, and thendyeing the print.

'3. The Within described improvement in the process of making coloredphotographic prints in graduated relief, the same consisting inincorporating a non-actinic coloring medium in the sensitized colloidcoating, exposing the sensitized coating to light, discharging saidcoloring medium after such exposure by means of an alkaline developer,

treating the developed relief print With a hardening and mordantingagent such as chromic acid, and then dyeing the print.

4. Thewithin described improvement in theprocess of making coloredphotographic prints in graduated relief, the? same consisting inincorporating a non-actinic and Water-soluble dye in the sensitizedcolloid coating, exposing said sensitized coating to light, developingthe print, discharging the dye, and then subjecting the print to itsappropriate dye bath.

In -testimony whereof, I havesigned my name to this specification, inthe presence of two subscribing witnesses.

/ rnnnnmo E. rvEs.

Witnesses:

F. C. MARTIN, FRED TAGLANG.

